Aerodynamic airfoils and their applications

This work focuses on aerodynamic airfoils and their application. The significant aim of this work is to introduce and analyse different types of airfoils and their importance. The first part of the paper examines aerodynamic characteristics, airfoil geometry and brings the historical evolution of certain types of airfoils. The second part of the paper considers different databases, and closely examines the NACA database and its numerical labelling by looking at digit series label, which follows the acronym NACA, indicating the airfoil's shape. The main body of the paperillustrates the real-life application of chosen airfoils by examining horizontal and vertical stabilisers and wind turbines. The last part of the paperpresents the analysis of the application of chosen wing root and wingtip airfoils.

Design and Fabrication of a Novel Window-Type Convection Device

Global warming, climate change, and ever-increasing energy demand are among the pressing challenges currently facing humanity. Particularly, indoor air conditioning, a major source of energy consumption, requires immediate improvement to prevent energy crises. In this study, various airfoil profiles were applied to create a window-type convection device that entrains air to improve convection between indoor and outdoor airflows and adjust the indoor temperature. How the geometric structure of the convection device affects its air entrainment performance was investigated on the basis of various airfoil profiles and outlet slit sizes of the airflow multiplier. The airfoil profiles were designed according to the 4-digit series developed by the National Advisory Committee for Aeronautics. The results revealed that airfoil thickness, airfoil camber, and air outlet slit size affected the mass flow rate of the convection device. Overall, the mass flow rate at the outlet of the convection device was more than 10 times greater than at the inlet, demonstrating the potential of the device to improve air convection. To validate these simulated results, the wind-deflector plate was processed using the NACA4424 airfoil with a 1.2 mm slit, and various operating voltages were applied to the convection device to measure the resulting wind speeds and calculate the corresponding mass flow rates. The experimental and simulated results were similar, with a mean error of <7%, indicating that the airfoil-shaped wind-deflector plate substantially improved air entrainment of the convection device to the goal of reduced energy consumption and carbon emissions.

Comparative study of symmetrical Vs asymmetrical Vs semi-symmetrical airfoils

Airfoils are the cross-section of the wing or blade. Extensive research in the maximum L/D ratio is crucial as faster travel is the need of the hour for developing faster and more efficient aircraft, for the military as well as transportation purposes. Hence to find the best aerodynamic property, we will study the 3 types of airfoils. Through this paper, the intention is to find out the best airfoil which can be applied for use. In this study, the comparison between symmetric, anti-symmetric, and semi symmetric airfoil characteristics are made using ANSYS Fluent. ANSYS Fluent offers us a platform to make simulations. Codes have been fed into the MATLAB software to generate the required coordinates. Airfoil design upholds great importance in modern-day design in aeronautics. The airfoils were designed using NACA guidelines and compared. This paper aims to find the advantages and disadvantages of the 3 different airfoils. The airfoils examined are made using coordinates derived from the NACA 4-digit series. Four different pitch angles were used: 0°, 2°, 4°, 8° to best replicate real-life applications. The main purpose of this is to find which of the 3 airfoils is the best based on Cd and Cl values for different attack angles. The Reynolds Number for each simulation will be the same for uniformity in the experiment. A high value of Reynold’s Number will be taken in the scale 106. Each airfoil cross-section was studied.

Airfoil to Improve Aerodynamic Performance OF Aileron Reduced Spanwise in Combat Helicopter

Combat helicopters frequently operate in the part of Planetary Boundary Layer (PBL) characterised by the presence of dust and many other aggressive agents, particularly, in desertic areas and in marine sites, so the aerodynamic performance of their ailerons reduced spanwise, carrying out weapon systems, may be reduced within unacceptable values and consequent relevant risks for the stability of the copter. According to some experts, ailerons for weapon systems of helicopter are not involved in the global lift of the copter, but their operative function is only to carry the combat systems..Nevertheless, some crash occurred to US combat helicopters suggest a different point of view, and an aileron damage, perhaps due to a kind of dynamic stall phenomenon, seems have been caused the copter fall. These problems may be avoided using particularly airfoil for the section of aileron instead of classic ones as NACA four digit series (as 00120018). These profiles may be FFA-W1-XXX series, characterised by a double curvature of camber-line. In the present paper, after a deep analysis of operative conditions of modern combat helicopters, the aerodynamic performance of aileron section as NACA 0018 and FFA-W1-182 have been analysed and compared, and the results of tests carried out on a water table test bench are exposed and discusses.

Design and Construction of NACA-4415 Airfoil with Various Shaped Surface Modifications

A fluid flowing over an object has a tendency to drag the object along it&rsquo;s flow direction. An object passing through a fluid which is stationary there is a tendency to slow the object down. For a stationary object in a fluid which is flowing there is a tendency to move the object in the fluid flowing direction .These tendencies of flowing fluid is known as drag. While moving through air airplanes also subjected to several drags. Airplanes subjected to pressure drag or form drag due to flow separation which is based on the pressure difference between the upstream and downstream surfaces of the object. Airplanes also subjected to Skin friction drag which results from the viscous shear of the fluid flowing over the object surface. In order to overcome these drags airplane wings cross section airfoils are designed very carefully. National Advisory Committee for Aeronautics, or NACA, developed and tested "families" of airfoils. Some of the most successful of these were the NACA four-digit and five-digit series. The necessary coordinates for designing NACA airfoil profiles are available in online. UIUC also provide coordinates for designing NACA airfoil profiles. But the present work describes the way of designing NACA four digit airfoils without taking any coordinates from available sources like google or any other search engines. Using C programming with the help of NACA provided equations a generalized source code is designed .Which will provide coordinates for designing any NACA four digit airfoil profiles .With the help of this obtained profile the wing model is also constructed using solid works. Using solid works model the real model was constructed using wood. The chord of regular surface airfoil is 21 cm and the span is also 21 cm. The airfoil profile taken for the model construction is NACA-4415 which is a four digit cambered airfoil.The present work also show some figures of an airfoil by applying certain surface modifications in form of dimples.

Aerodynamic Devices for Formula Student Race Cars

Formula Student race cars are getting more competitive and hence enhancements of the car aerodynamics, although the top speeds are not exceeding 140 km/h, are getting more important in order to have a competitive race car. Therefore aerodynamic packages consisting of several aerodynamic devices are being developed. Especially the front and rear inverted airfoils or wings have a major influence on the dynamic behaviour of the car. These wings are designed in order to develop a maximum down force at still acceptable drag. The Reynolds number is about 5×105. However, most of the airfoils and corresponding available airfoil data were developed for Reynolds numbers of the order of 3×106<Re<8×106. The lift coefficient of an airfoil is basically determined by its camber, the distance of the maximum camber from the leading edge, thickness and the shape of the airfoil, as well as by the angle of attack. The NACA 4 digit series of airfoils allows controlling these parameters exactly. Therefore a study was performed analyzing over 500 different NACA 4 digit airfoils configurations systematically by variation of these parameters and studying its impact on the lift and drag coefficients at Reynolds numbers of 5×105. Based on these airfoils the aerodynamic design process is described. Full car CFD simulations with ANSYS CFX of the race car with and without aerodynamic package are shown and compared. Detailed quantitative analysis of the forces on the wings and the whole car are presented without and with the aerodynamic package.

Circumventing the polydactyly ‘constraint’: the mole's ‘thumb’

Talpid moles across all northern continents exhibit a remarkably large, sickle-like radial sesamoid bone anterior to their five digits, always coupled with a smaller tibial sesamoid bone. A possible developmental mechanism behind this phenomenon was revealed using molecular markers during limb development in the Iberian mole ( Talpa occidentalis ) and a shrew ( Cryptotis parva ), as shrews represent the closest relatives of moles but do not show these conspicuous elements. The mole's radial sesamoid develops later than true digits, as shown by Sox9 , and extends into the digit area, developing in relation to an Msx2 -domain at the anterior border of the digital plate. Fgf8 expression, marking the apical ectodermal ridge, is comparable in both species. Developmental peculiarities facilitated the inclusion of the mole's radial sesamoid into the digit series; talpid moles circumvent the almost universal pentadactyly constraint by recruiting wrist sesamoids into their digital region using a novel developmental pathway and timing.

Foil Definition for Optimizing the Shape of Microfabricated Columns for Capillary Electrochromatography

A novel design approach for optimizing the shape of the microfabricated pillar columns [1] for capillary electrochromatography (CEC) is presented. Applying this optimization approach, a new foil shape definition was introduced. Several design alternatives were evaluated starting from typical NACA 4-digit series symmetric airfoil definition. In order to avoid stagnant regions over the leading edge for NACA airfoil, the maximum thickness point was defined at the center of the chord. Then this shape was defined as the intersection of two parent circles to create the same geometry with simpler definition. As a final step of the optimization, a custom foil shape was obtained by fitting the 4th order polynomial, which was obtained from typical NACA 4-digit series, according to the defined boundary conditions. Microfluidic flow simulations were performed for electroosmotic flow (EOF) case for evaluating the performance of the foil definitions over other popular geometries (diamond and hexagon) from literature [2]. For electric field of 100 V/cm and same length and width, the custom foil shape yielded a plate height value of 2.76 μm, while 2.85 μm was obtained with hexagon as being the lowest value among other alternatives from the literature.

Effects of a Transformational Mnemonic Strategy to Facilitate Digit Span Recall by Mildly Handicapped Students

24 mildly handicapped students were taught two 9-digit numbers in a cross-over design in which number of digits and order of presentation of condition were counterbalanced. In the cluster-rehearsal condition, students were taught the digit series in clusters of three with overt experimenter-led rehearsal. In the mnemonic condition, numbers were transformed into isomorphic pictorial representations of concrete objects and pictured as appearing on the head, hand, and foot of a man, woman, and child, respectively, in each of three pictures. Free and cued recall scores were collected on immediate and three delayed recall intervals, and scored for position, sequence, and span scores. Recall data were obscured by ceiling effects but consistently favored mnemonic instruction. Cued recall scores collapsed across recall intervals statistically favored mnemonic instruction according to nonparametric tests. In addition, as in previous investigations of mnemonic instructions, response latencies were significantly greater under mnemonic instruction. Finally, collapsed item-position scores showed bowed serial-position curves in cluster-rehearsal but not mnemonic conditions. Implications for further research are given.